Vasoactive drugs

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Vaso-active drugs By Dr. Ahmed Galal PICU specialist

Transcript of Vasoactive drugs

Page 1: Vasoactive drugs

Vaso-active drugs

By Dr. Ahmed Galal

PICU specialist

Page 2: Vasoactive drugs

Definition of vasoactive drugs

These are drugs that has effect on heart & circulatory

system

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Adrenergic receptors

Β receptors α receptorsβ2 β1 α2 α1

• Sm.ms. Relaxation in bronchioles, blood vs., uterus

• Increase renin• Gluconeogenesis

& glycolysis

• Heart: intropy, chronotropy & improve ejection fraction

• Increase renin

• Inhibits insulin release

• Stim. Glucagon release

• Inhibit noradrenaline relase

• VC of bl.vs. of skin, GIT, kidney, brain

• Sm.ms. Contraction of uterus, ureter, cilliary body

• Gluconeogenesis & glycolysis

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Classification of vasoactive drugs

Vasopressor Inotropic Vasodilator

AdrenalineNoradrenaline

Phenyl epherineVasopressin

Ephidrine

DopamineDobutamine

AmrinoneMilrinone

AdrenalineDigoxinCalcium

Na NitroperrusideNitroglycerine

Hydralazine

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AdrenalineMechanism of action:

It stimulates α1 & β1 & 2 adrenergic receptors

Vasoconstriction causing hypertension

Inotropic & chronotropic effect

Bronchodilatationantishock

Action: Indications:

Shock (all types)Heart failure

Asthma & croupAnaphylaxis

Nasal obstruction & local haemostasis

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AdrenalineDosing

Shock (IV or IO): 0.05 – 1 mic/kg/min.Anaphylaxis or asthma (IM or SC): 0.1 ml/kg of 1/1000 solution

Arrest (IV or IO): 0.1 ml/kg of 1/10,000 solutionArrest (ET): 0.1 ml/kg of 1/1000 solution

Side effectsTachycardia & tachy-arrythmia

Renal impairment & urine retention (in high doses)Rebound bronchospasm

Skin necrosisMesenteric vaso-constiction & ischemia (in high doses)

RFVF

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Nor-adrenalineMechanism of action:

It stimulates α1 & weaker on β1 adrenergic receptors

Vasoconstriction causing hypertension

Very weak Inotropic & chronotropic effect

Action: Indications:

Shock (hypotensive& vasoplegic)

Can be used in hypotensive fallot tetralogy patient

with cyanotic spell

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Nor-adrenalineDosing

Shock (IV or IO): 0.05 – 2 mic/kg/min.

Side effects

Renal impairment even in low dosesSkin necrosis esp. if extravasated

Mesenteric vaso-constiction & ischemia (in high doses)Tachycardia & tachy-arrythmia to a lesser extent

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DopamineMechanism of action:

It stimulates α1, α2, β1& to a lesser extent β2 adrenergic receptorsIt also stimulates dopaminergic receptor (DA1 & DA2)

Low dose: ++ DA1 & DA2Intermediate dose: ++ β

High dose: ++ α1

Action: Systematic action:

Low doses: for mesenteric ischemia

Intermediate dose: cardiac & septic shock

High doses: hypotensive shock

Renal dose become obsolete

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DopamineDosing

Low dose: 2 – 5 mic/kg/minIntermediate dose: 5 – 10 mic/kg/min

High dose:10 – 20 mic/kg/min

Side effects

Tachycardia & tachy-arrythmiaSkin necrosis if extravasated

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DobutamineMechanism of action:

It stimulates β1 & very mild β2& α1 adrenergic receptors

Inotropic & chronotropic effect

May cause mild vasodilatation

Action: Indications:

Heart failureCold septic shock with normal blood pressure

With noradrenaline to save mesenteric vasculature

Improve the diastolic

dysfunction

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DobutamineDosing

5 – 20 mic/kg/min may increase to 30 mic

Side effects

Tachycardia & tachy-arrythmiaSkin necrosis if extravasation

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MilrinoneMechanism of action:

It is phosphodiesterase inhibitor so, increase cAMP that lead to increase Ca delivery to myocardium

Inotropic & chronotropic effect

Vasodilatation (pulmonary & systemic)

Action: Indications:

Cardiac failurePulmonary hypertension

Cold septic shock with normal blood pressure

Improve the diastolic

dysfunction& Rt sided failure

Inhalation in pulmonary

hypertension

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MilrinoneDosing

0.5 – 0.75mic/kg/min

Side effects

HypotensionTachycardia & tachy-arrythmia

ThrombocytopeniaShould be adjusted in renal imaprement

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VasopressineMechanism of action:

It stimulates VR1 causing increase cAMP that lead to increasing Ca delivery to bl. Vs wall

Vasoconstriction causing hypertension

Water retention causing renal impairment

Decrease intestinal motility & gut ischemia

Action: Indications:

Profound hypotensionDI

GI bleeding

ADH analogue

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VasopressineDosing

0.0005 – 0.01mic/kg/hr

Side effects

Anuria & renal failureSevere mesenteric ischemia

Hyponatremia

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Vasodilator drugsInhibits ACE so, decrease angiotensin 2 (potent VC)

Captopril, ramipril

ACE inhibitors

Competitive inhibition to angio 2 receptors

Losartan Angiotengen 2 receptor antagonist

Block Ca entrance to vascular wall causing relaxation

Nifidipine, amlodipine

Ca channel blockers

NO donor, increase cGMP causing relaxation

Nitroglycerine, nitroperusside

Nitrates

Comprtitive inhibition of α1 receptors

Phentolamine Adrenoreceptor antagonists

Bind to dopaminergic receptors Fenoldapam Dopaminergic receptor agonists

Bind to PG receptor increasing cGMP

alprostadil Prostaglandin

Direct areriolar dilatation Hydralazine

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NitroglycerineMechanism of action:

It is NO donor so, stimulation of cGMP causing vascular wall relaxation

Vasodilator mainly veinsDecrease myocardial oxygen

demands (by improving atrial filling pressure by

venodilatation)

Action: Indications:

Heart failureCold septic shock with normal blood pressureHypertensive urgencies

Cautious use in shock

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NitroglycerineDosing

0.5 – 5 mic/kg/min upto 20 mic/kg/min in hypertensive emergencies

Side effects

Tachycardia, hypotensionPrespiration

Headache

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NitroperossideMechanism of action:

It is NO donor so, stimulation of cGMP causing vascular wall relaxation

Vasodilator mainly arteriolarHypotension

Action: Indications:

Hypertensive urgencies

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NitroperossideDosing

0.5 – 1 mic/kg/min

Side effects

Tachycardia, hypotensionHeadache

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Thank you